1. Field of the Invention
This invention relates to the art of slide fasteners and more particularly to a slide fastener stringer which is made air-tight or water-tight to suit applications such as in wet-suits, fishing boots, and other water-proof articles.
2. Prior Art
There are known numerous slide fasteners of a water-tight or air-tight construction, a typical example of which comprises, as disclosed in British Pat. No. 723,998, a pair of support tapes each carrying a series of discretely arranged coupling elements, the tape material being folded around the major portions of the elements. The elements thus masked by the tape material are further enveloped by sealing strips or stirrups to make the fastener watertight. This enveloping operation has encountered considerable difficulty in that failure to maintain the individual fastener elements in equally spaced-apart relation or to support them stably in position on the tapes would make it difficult to register the stirrup with the elements to be enveloped. Furthermore, unfilled spaces between the elements and the tapes would invite entry of foreign matter which would interfere with normal coupling and uncoupling performance of the fastener stringer.